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How Webmin can ease DNS management

Working for an Australian ISP in the mid-1990s, Jamie Cameron was swamped with users' DNS record-change requests. Surely, he thought, there has to be a better way to handle DNS changes than editing BIND configuration files. With that thought and a couple of years' work, Melbourne, Australia-based Cameron came up with Webmin, a program that can simplify Unix or Linux management. Webmin can help IT managers make quick work of daily chores like creating Apache virtual hosts or DNS zones, Cameron said. In this interview, he offers an introduction to Webmin and describes some ways to use it in enterprise settings. For an in-depth look at Webmin's workings, Cameron offers a new book, Managing Linux Systems with Webmin, which is part of Bruce Perens' open-source series from Prentice Hall PTR.

Could you elaborate on why you created Webmin?
At the time, I was managing a DNS server for the company that I worked for, among other things. I got a lot of requests to add or change DNS records from people that I didn't trust to make those changes themselves by directly editing the BIND configuration files. Since this took up a lot of my time, I came up with the idea of a Web interface for managing the DNS server. Less experienced people could safely use it to edit the DNS configuration, while being prevented from messing up configuration files or performing other tasks.

This gave me the idea to write a more general program for managing all kinds of Unix configuration files through a Web interface, which I called 'Webmin.' These days, the use of a Web browser as a user interface is common, but in those days it was quite a new idea. What can Webmin do for system administrators handling enterprise Linux environments? For example, your book mentions authorizing Webmin access to delegate tasks to junior IT staffers.
Even an experienced admin on an enterprise system can still benefit from Webmin's user interface, which checks user inputs and always creates valid configuration files. It can also speed up common tasks like creating DNS zones or Apache virtual hosts, through its ability to define templates containing initial settings for new zones or hosts.

That said, Webmin may be best suited to use by less experienced users who are unfamiliar with configuration file formats than enterprise sys admins who already have a detailed understanding of Unix. Could you describe one of the tasks Webmin handles in more detail?
One very useful feature is the ability to create multiple Unix users at once from a batch file containing their user name, real name and other details. This will also create home directories containing initial dot files, and can even set up default quotas for new users or create Samba logins for them as well. This would be harder to do in any other way, even for an experienced script writer. How has Webmin changed since its first release in 1997?
I'll just name a few. Many more modules for managing different servers and services have been added. The user interface has totally changed at least twice. And more operating systems are supported; the original was only for Solaris and Linux. Also, finer-grained access control has been added. Could you describe a set of tools that would make a good enterprise Webmin-plus 'bundle'?
Webmin is really just a configuration tool, so it needs servers like Apache, Sendmail, Squid, Samba and MySQL to configure. These all come with common Linux distributions like Red Hat, so Webmin is a good choice to install on a fully loaded Linux system. When shouldn't Webmin be used in business settings?
It shouldn't be used on systems that have already been configured by an experienced sys admin using scripts to edit configuration files and perform other tasks. Because it edits configuration files directly, it almost certain won't fit in with the way such a system is currently being managed. How can Webmin streamline server status monitoring?
It has a module for simple status monitoring that can check various servers (such as Squid, Apache and Sendmail) and services (such as pinging a host or connecting to a TCP port) on schedule. If something is found to be down, an e-mail can be sent or a command run to fix the problem.

There are also modules for configuring more sophisticated status monitors like Mon and NetSaint, so that you don't have to edit their configuration files directly. Drilling down in server status monitoring, could you describe how Webmin tests remote HTTP service?
It makes a connection (possibly in SSL mode) to a specified server and port, then sends a request for a page, optionally with an HTTP login and password. If the request comes back with a non-error HTTP status, then the Web server is considered to be up.

What are comparable commercial products?
I guess any kind of GUI administration tool is comparable, such as SAM for HP-UX, Solaris' Netra interface, SMIT for HP-UX and probably others that I don't know about. In the Linux world, Linuxconf is the biggest competitor, as it performs a very similar task, but it is mainly for use via X11 [rather] than through a Web browser. Drilling down in server status monitoring, could you describe how Webmin tests remote HTTP service?

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